Taking stock of the assisted migration debate

Assisted migration was proposed several decades ago as a means of addressing the impacts of climate change on species populations. While its risks and benefits have been debated, and suggestions for planning and management given, there is little consensus within the academic literature over whether to adopt it as a policy. We evaluated the main features of the assisted migration literature including the study methods, taxonomic groups, geographic regions and disciplines involved. We further assessed the debate about the use of assisted migration, the main barriers to consensus, and the range of recommendations put forth in the literature for policy, planning or implementation. Commentaries and secondary literature reviews were as prevalent as first-hand scientific research and attention focussed on a global rather than regional level. There was little evidence of knowledge transfer outside of the natural sciences, despite the obvious policy relevance. Scholarly debate on this topic has intensified during the last 3 years. We present a conceptual framework for evaluating arguments in the debate, distinguishing among the direct risks and benefits to species, ecosystems and society on the one hand, and other arguments regarding scientific justification, evidence-base and feasibility on the other. We also identify recommendations with potential to advance the debate, including careful evaluation of risks, benefits and trade-offs, involvement of relevant stakeholders and consideration of the complementarity among assisted migration and less risk-tolerant strategies. We conclude, however, that none of these will solve the fundamental, often values-based, challenges in the debate. Solutions are likely to be complex, context-dependent and multi-faceted, emerging from further research, discussion and experience.     

The contribution of diatoms to bioflocs lipid content and the performance of juvenile Litopenaeus vannamei (Boone, 1931) in a BFT culture system

This study aimed to evaluate the contribution of three diatom species on the lipid content of bioflocs, their permanence on the bioflocs and influence on the growth performance of juvenile shrimps. Juveniles of Litopenaeus vannamei were reared (30 days; three replicates per treatment) in biofloc systems inoculated with diatoms Amphora coffeaeformis (A), Cylindrotheca closterium (C), Conticribra weissflogii (W), or biofloc only (BF, chlorophycean rich). Water quality parameters were monitored daily and the microbiota on days 1, 10, 20 and 30. The lipid content and fatty acid profiles of bioflocs were analyzed at the end of the experiment. Shrimp survival rate (99%) at treatment A was significantly higher than at BF. The bioflocs in A treatment presented the highest lipid content, differing significantly from BF and W. The content of EPA (20:5) (n‐3) was significantly higher in A and lower in BF, while linoleic acid (18:2) (n‐6) was significantly higher in BF. The results indicate that high cell density of diatoms can be successfully maintained with silicate addition in biofloc systems and that the pennate A. coffeaeformis and the centric C. weissflogii are potentially better suited than the pennate C. closterium as food supplements for shrimp diets in biofloc nurseries system.     

Female White-Tailed Deer Body Condition and Diet After a Large Spring Wildfire

Frequency of large rangeland wildfires may increase in the southwestern United States and northeastern Mexico as a result of exotic grass invasion and reduced emphasis on livestock production, but effects of such fires on white-tailed deer (Odocoileus virginianus) are poorly documented. A large wildfire burned &spigt; 90% of the 6 151-ha Chaparral Wildlife Management Area in southern Texas during March 2008, creating an opportunity to study short-term effects of wildfire on white-tailed deer food habits, body condition, and pregnancy. We harvested 26 female deer between 7 April and 20 June 2008 and recorded dressed body weight, body condition, number of corpora lutea, and number and size of fetuses. We used rumen contents to quantify forage classes consumed. Deer ate prickly pear (Opuntia engelmannii) pads and emergent grasses during April and shifted to forbs and browse as vegetation communities recovered. Deer consumed mesquite (Prosopis glandulosa) beans and prickly pear fruit during mid-June. Body condition measures did not vary during the collection period, suggesting deer were able to acquire sufficient nutrients to meet requirements. Fetal development rate appeared normal. Precipitation (11.4 cm) during late April and May probably allowed vegetation to recover from the wildfire. White-tailed deer are resilient opportunists and were able to maintain body condition and pregnancy after a large-scale wildfire.     

The severely under‐recognized public health risk of strongyloidiasis in North American cities—A One Health approach

Strongyloides and other soil‐transmitted helminths represent a severely under‐recognized zoonotic public health risk, especially in North American cities. They are present throughout North America, including in urban areas, causing morbidity and mortality in human and non‐human animals. Epidemiological “masking” of strongyloidiasis due to overlapping symptoms with other systemic diseases, including allergies, and diagnostic limitations complicate our understanding of the epidemiological extent of this disease, and auto‐infection allows long‐term persistence of individual infections. Zoonotic transmission and environmental transmission are critical components in the epidemiology of strongyloidiasis, and other diseases caused by soil‐transmitted helminths. In this review, we bring together medical, veterinary and environmental expertise in a “One Health” context, to document and analyse this under‐recognized risk. We also present implementable opportunities for action with respect to diagnostics, treatment, community engagement and land management to mitigate the impact and transmission of strongyloidiasis and other diseases caused by soil‐transmitted helminths.